The invention relates to an electronic apparatus having a plurality of electronic equipments contained in a rack, which electronic equipments have electronic parts each making a heat source, and to an electronic equipment.
FIG. 8 is a plan view showing the construction of conventional electronic equipment. In FIG. 8, the reference numeral 1 denotes a rack, 2 electronic equipments, 3 a fan, 4 electronic parts constituting heat sources, 5 fins for radiating heat from the electronic parts 4, 6 covers which cover the electronic parts 4, and 17 is an electronic apparatus comprising these elements. Also, FIG. 9 is a cross sectional view taken along the line A-Axe2x80x2 of the electronic equipment 2. In FIG. 9, the reference numeral 7 denotes a chassis, 8 a package, 9 an inner casing, 10 fin-inbetween wind paths, and 11 a bypass wind path. In addition, in FIG. 9, the same reference numerals as those in FIG. 8 denote the same or corresponding parts, and so an explanation thereof is omitted.
An explanation will be given below to the constitution. As shown in FIG. 8, a plurality of electronic equipments 2 are arranged in the rack 1 such that the fins 5 and covers 6 face each other. Provided between adjacent electronic equipments 2 is a clearance (gap), which facilitates mounting of the electronic equipments 2 and work for maintenance and replacement. Mounted on these electronic equipments 2 are electronic parts 4, from which heat generates during action. The fins 5 extending from an upstream side, where an air inflows, to a downstream side are arranged in plural on a back surface of the chassis 7, on which the electronic parts 4 are mounted. Conventionally, die casting is used to form the fins 5 integral with the chassis 7. Die casting is a method of forming, in which a casting die is manufactured and a molten metal such as aluminum alloy or the like is injected into the casting die.
The fin-inbetween wind paths 10(FIG. 9) are passages of an air flowing between adjacent fins 5. And the bypass wind path 11 is a passage of an air not flowing into the fin-inbetween wind paths 10. The bypass wind path 11 means a clearance between adjacent electronic equipments 2, that is, a passage of an air flowing between the fins 5 and the cover 6 of predetermined electronic equipments 2, and also means a passage of an air flowing between the fins 5 and inner walls of the rack 1. The rack 1 is provided with the fan 3, which supplies an air to an interior of the rack 1. In addition, the fins 5 and the chassis 7, which have been integrally formed, in combination is called a heat sink.
An explanation will be given below to the action. The electronic parts 4 mounted in the respective electronic equipments 2 generate heat during action. The electronic parts 4 reach a temperature of about 100xc2x0 C., and 140xc2x0 C. or higher when high. Heat generated from the electronic parts 4 is transmitted to the package 8, inner casing 9, chassis 7, and the fins 5 shown in FIG. 9. Meanwhile, the fan 3 supplies an air to the interior of the rack 1 to create flows of wind passing through the fin-inbetween wind paths 10 and the bypass wind path 11. Heat transmitted to the fins 5, of heat generated from the electronic parts 4 is finally dispersed by wind flowing through the fin-inbetween wind paths 10. In this manner, since heat generated from the electronic parts 4 is mainly dispersed by wind flowing through the fin-inbetween wind paths 10, working of heat in the electronic parts 4 is suppressed.
With the electronic apparatus described above, the plurality of electronic equipments 2 are contained in the rack 1 with predetermined gaps between adjacent electronic equipments 2, as the result of taking account of workability in mounting, maintenance and replacement. In such electronic apparatus, a part of an air supplied from the fan 3 flows into the bypass wind path 11 and the remainder of the air flows into the fin-inbetween wind paths 10. In order to enhance the heat radiation efficiency of the electronic equipments 2, it is sufficient to increase an amount of an air flowing into the fin-inbetween wind paths 10 and to decrease an amount of an air flowing into the bypass wind path 11. FIG. 10 is a graph showing a ratio of air volumes flowing through fin-inbetween wind paths and a bypass wind path, and an illustration thereof. As shown in FIG. 10A, a bypass air volume (B) flowing into the bypass wind path 11 amounts to 35% of a total air volume, which is a total amount of an air supplied by the fan 3. FIG. 10B shows a manner, in which an air flows into the fin-inbetween wind paths and the bypass wind path. A ratio of a fin-inbetween air volume and a bypass air volume in the total air volume is determined by balancing of wind-path resistances in the fin-inbetween wind paths and the bypass wind path.
Hereupon, in the case where four electronic equipments 2 are mounted within the rack 1 as in the electronic apparatus shown in FIG. 8, four sets of the fin-inbetween wind paths and the bypass wind path are naturally defined. The fin-inbetween wind paths and the bypass wind path are described below as xe2x80x9cwind pathsxe2x80x9d. It has been revealed that an air taken into the rack 1 by the fan 3 does not flow evenly into the four wind paths but air volumes flowing into the respective wind paths scatter 20% at the maximum. Since air volumes flowing into the respective wind paths are uneven, the respective electronic equipments 2 scatter in heat radiation efficiency. That is, there is possibly caused the situation that among the electronic equipments mounted within the rack 1, those electronic equipments, for which a large amount of air flows into the wind paths, efficiently radiate heat but those electronic equipments, for which a small amount of air flows into the wind paths, do not act normally due to overheat. The reason why air volumes flowing into the respective wind paths scatter is believed to be due to scatter in wind-path resistance (pressure loss) for the respective wind paths, wind speed distribution within the rack 1, positions where the electronic equipments 2 are mounted, and the like.
In order to permit the respective electronic equipments 2 within the rack 1 to evenly radiate heat, it is necessary to suppress scatter in air volumes flowing into the four wind paths. In order to suppress scatter in air volumes flowing into the respective wind paths, measures have been conventionally adopted, in which a spacing between adjacent fins 5, that is, fin pitch is modified to adjust pressure loss (wind-path resistance) in fin-inbetween wind paths. When pressure loss is adjusted by modification of fin pitch, however, there is caused a problem that the electronic equipments 2 are lowered in heat radiation efficiency since balancing of pressure loss between the fin-inbetween wind paths and the bypass wind path is lost to permit an air flowing into the fin-inbetween wind paths to pass through the bypass wind path. Also, it is difficult to manufacture a heat sink of small fin pitch with the use of die casting. The reason for this is that resistance encountered when a molten metal is poured into tip ends of a casting die increases as the fin pitch becomes narrow and so high pressures must be applied when a molten metal is poured into the casting die. Also, since an area, at which the molten metal contacts with inner surfaces of the casting die, increases, the molten metal frequently solidifies before it reaches tip ends of the casting die, and so it is difficult to obtain a fin configuration in accordance with a design.
The invention has been accomplished to solve the above-mentioned problems and has its object to eliminate scatter in air volumes flowing into a plurality of wind paths formed between a plurality of electronic equipments contained in a rack of an electronic apparatus.
An electronic apparatus according to the invention comprises an electronic equipment or equipments having a plurality of fins arranged to extend from an upstream side, where an air inflows, to a downstream side, a chassis permitting heat of heat generating electronic parts to be radiated through the fins, and a cover which covers the heat generating electronic parts; a rack containing therein a plurality of the electronic equipments, on which the fins of and the cover of adjacent electronic equipments face each other with a predetermined distance therebetween, the rack being formed with a plurality of wind paths, which are composed of fin-inbetween wind paths being passages of an air flowing between the fins, and bypass wind paths being passages of an air flowing between the fins of and the cover of adjacent electronic equipments; a fan for supplying an air into the rack and creating air flows passing through a plurality of wind paths formed within the rack; and pressure-loss adjusting members mounted on downstream sides of predetermined wind paths, in which an amount of inflowing air is relatively much, among the plurality of wind paths, to make a downstream-side cross sectional area of the predetermined wind paths smaller than a upstream-side cross sectional area thereof, thereby increasing pressure loss of the predetermined wind paths.
An electronic equipment, according to the invention, is arranged in plural within a predetermined housing to be spaced a predetermined distance from one another, each mounting thereon heat generating electronic parts generating heat, which is radiated by an air supplied into the housing, and the electronic equipment comprises a chassis, on which a plurality of fins are formed on an opposite side to a surface, on which the heat generating electronic parts are mounted, to extend from an upstream side, where an air inflows, to a downstream side, the chassis permitting an air flowing between the fins to radiate heat from the heat generating electronic parts, and a pressure-loss adjusting member formed to cover downstream-side end surfaces of the fins such that a wind path composed of fin-inbetween wind paths, which are passages of an air flowing between the fins, and a bypass wind path, which is a passage of an air flowing between adjacent electronic equipments, has a downstream-side cross sectional area larger than a upstream-side cross sectional area thereof.